Arrangement for transferring and utilizing heat energy

ABSTRACT

Arrangement for transferring heat energy from a unit like heat power plant ( 1 ) which produces heat energy or from heat source locating in the nature, like from sea to a unit which utilizes heat energy, in which arrangement heat energy is transferred through a pipe system ( 2, 3 ),( 16 ) and water functions mainly as a heat transfer medium. Heat energy is transferred at such a delivery temperature of the heat transfer medium—at least at a temperature of +20 ° C., but under 60° C.—that in order to utilize the heat energy the above mentioned temperature has to be changed with the help of a heat pump ( 8 ) to be suitable for utilisation.

The invention relates to an arrangement in order to transmit and utilize heat energy from a unit which produces heat energy to a unit which utilizes heat energy in which arrangement heat energy is transferred through a pipe system with water that functions mainly as a heat transfer medium.

Energy plants, the ground, water systems and for example industrial processes are previously known as units that produce heat energy. Of these objects energy plants and industrial processes deliver it at such a temperature that it can be utilized directly or its temperature can even be lowered when they sell heat energy.

Heat energy from the ground or the water system is known as free energy that is transferred to a usage target with the help of pipe systems and with the help of the liquid circulating in them. The temperature of the liquid when it is being transferred is however so low—usually under +10° C.—that its temperature has to be increased with the help of a heat pump to a level where it can be utilized better. The disadvantage of this free energy is the fact that it is hard to get during cold weather and usually transfer distances of this free energy are limited to a couple of hundred meters. There is a lot of heat energy also at a temperature that is lower than the temperatures that are used in the district heating network and respectively at a temperature which is higher than the temperature of the ground and the temperature of the water system. The present invention has a solution for utilizing this kind of energy the temperature level of which varies between approximately +10° C.-50° C. in a new way. It is characteristic of the arrangement according to the invention regarding the transfer from the heat producing unit to the utilizer that heat energy is transmitted at such a delivery temperature of the heat transfer medium—at least at a temperature of +20° C., but under 60° C.—that in order to utilize the heat energy the above mentioned temperature is changed at the end of the user unit with the help of a heat pump in order to be suitable for utilization.

Other characteristic features of the invention are presented in the dependent claims. The advantage of the arrangement according to the invention is the fact that heat energy can be transmitted long distances in pipe systems which are constructed of plastic in the same way as district heating, heat losses during transfer are minor due to a low temperature and that also the energy of the heat pump to be utilized can be fully utilized at the user end. Due to the low temperature of the transferred energy it is possible to use this energy in the summer time also to cool down buildings because the temperature of the transferred energy can be arranged to the needed temperature level, approximately to a value +10° C. with the help of one part of the arrangement or also in such a way that a hot intermediate agent that comes from the compressor in the cooling system is condensed to the temperature of this transferred liquid the temperature of which is lower than for example the outside temperature during hot weather. If sea water is the heat source, the temperature difference between the sea surface and bottom can be utilized by placing vapour/liquid circulation process to function by means of the temperature difference so, that a rotation motion producing power craft can be get in connection with the process either to produce electricity by means of a generator or to give rotation motion for example to a compressor in a heat pump.

In the following the invention is described more detailed by referring to the accompanying drawing in which

FIG. 1 shows an arrangement according to the invention as a diagram.

FIG. 2 shows an arrangement, where sea water is an energy source.

One arrangement according to the invention is shown in FIG. 1 as a diagram in which arrangement heat energy can be obtained from an energy plant 1 or from a similar process at a clearly higher temperature than what one could get as heat from the ground or as a heat from the water system as free energy. The temperature is however clearly lower than the temperature that is delivered by energy plants in the district heating networks. The invention relates to the transferred heat energy the temperature of which varies in the scale of about +30° C.-60° C. in this example which heat energy is delivered with the help of delivery/return pipe systems 2, 3 to customers. The temperature level is such that only by using heat exchangers hot household water cannot be produced from this temperature level at a temperature that is according to the regulations. The return temperature of the water used in the transfer of the energy is in this example between +5° C.-35° C.

The arrangement according to the invention comprises therefore a heat pump 8 with the help of which the temperature level is risen to a desired level with a very good operating efficiency. The arrangement comprises units for heat transfer known as such, like an evaporator 4, a condensing apparatus 7 and the water lines LV and KV and the circulating cycle of the cooling agent of the heat pump 8 in order to organize heating water and household water according to FIG. 1. Water line LV is hot water line to the building and KV is cold water line to the building. Energy recovery from the exhaust air of the building is carried out by means of heat exchanger 9 (LTO), with which exhaust air is cooled.

The cooling unit 5 can be connected to the return pipe system 2 according to the FIG. 1 if water temperature there is low enough. Another way is of course to take the cooling power directly from the evaporator 4 of the heat pump.

Extra process heats can be directed also by using delivery/return pipe systems from the industry processes, like from unit 6 to the condensing apparatus 7 also as a remote, if parallel heat sources are available.

In FIG. 2 sea water is as a heat source, the temperature of which is in deep place for example +5° C. and near the surface of the sea +25° C. A condenser 10 of a vapour/liquid circulation is placed in the deep place and a evaporator unit 11 respectively near the surface of the sea. In the deep place in the condenser 10 condensed medium is pumped by means of a pump 12 to an evaporator 11 wherein pressure of the medium increased due to increased temperature. Medium evaporates in the evaporator 11 due to heat energy which is transferring from the sea water to the evaporator. Pressure increase in the evaporator 11 higher than in the condenser 10 is utilized by leading the medium to rotate a motor 13 simultaneously than it returns into the lower pressure space in the condenser 10. It is advantageous to use as such medium whose vapour pressure at temperature +5° C. is over 5 bar, like carbon dioxide. The motor 13 has been mounted to rotate a electric generator 14 and also a coupling is adapted to the device, where the motor 13 can rotate the heat pump 8.

In the example of the FIG. 2 there is also utilized heat energy of the sea water as a free energy for the heat pump by leading sea water via line 16 to the evaporator 4 of the heat pump 8, which cools the sea water before it is returned via line 17 back to the sea. The cooled water in the line 17 can be utilized in cooling of different spaces by means of a heat exchanger. The heat pump 8 gets energy at very good temperature for lifting to a higher temperature level in the condenser 7.

The lines 16 and 17 can be relative long in the example of the FIG. 2, so that the actual heat pump plant 8 can located on the seashore and also farther from the seashore where users like buildings and living quarters locate. In this case preferable each building has its own heat pump unit 8 with needed heat exchangers 4, 7.

The heat engine 10-13 in the FIG. 2 can also be adapted to function in winter time between outdoor air and available free energy having temperature about 20°-50° C. In this case the condenser is placed outdoors at cold weather and the evaporator 11 is placed to take the evaporation energy of the medium from the free energy available. 

1. Arrangement for transferring heat energy from a unit which produces heat energy like from heat power plant (1) or from heat source locating in the nature, like from sea to a unit which uses heat energy in which arrangement heat energy is transferred through a pipe system (2, 3),(16) and water functions mainly as a heat transfer medium, characterized in that heat energy is transferred at such a delivery temperature of the heat transfer medium—at least at a temperature of +20° C., but under 60° C.—that in order to utilize the heat energy the above mentioned temperature has to be changed with the help of a heat pump (8) to be suitable for utilisation.
 2. Arrangement according to claim 1, characterized in that heat energy is transferred to remote users through delivery/return pipe systems (2, 3) which are sunk into the ground and the temperature of the transferred energy is increased by means of the heat pump (8).
 3. Arrangement according to claim 1, characterized in that the temperature of the transferred energy is lowered with the help of the heat pump (8).
 4. Arrangement according to claim 1, characterized in that the delivery temperature of the heat transfer medium varies between +20° C.-50° C.
 5. Arrangement according to claim 1, characterized in that the temperature of the return pipe system (2),(17) is utilized in a cooling process.
 6. Arrangement according to claim 1, characterized in that a heat producing or delivering unit (1) is a heat energy plant, an industrial process or energy taken from nature.
 7. Arrangement according to claim 1, characterized in that free energy taken from nature is transferred by means of heat engine (10-13) to rotation motion, which is lead to rotate a generator (14) and/or the heat pump (8).
 8. Arrangement according to claim 1, characterized in that the transferring line of the heat energy (2, 3);(16,17) is lead separately to each utilizer, wherein each utilizer has at least a heat pump unit (8) with needed heat exchangers (4),(7).
 9. Arrangement according to the claim 1, characterized in that the heat engine (10-13) is mounted to function between outdoor air, preferable cold air and available free energy having temperature about +20° C.-50° C. 